ORDB.org is shutting down
ordb.org was one of the rare open-relay rbl (Realtime Blackhole List) that would actually perform a check on the servers before blacklisting them. You could always remove your servers after correcting the problem since ordb would also perform a check before removing a server from its RBLs. It was my favorite RBL and it's shuting down:
We regret to inform you that ORDB.org, at the ripe age of five and a half, is shutting down. It's been a case of a long goodbye as very little work has gone into maintaining ORDB for a while. Our volunteer staff has been pre-occupied with other aspects of their lives. In addition, the general consensus within the team is that open relay RBLs are no longer the most effective way of preventing spam from entering your network as spammers have changed tactics in recent years, as have the anti-spam community.